textproduct: Quad Cities

KEY MESSAGES

- Warm temperatures combined with low humidity levels and windy conditions will create an elevated fire risk late this morning and afternoon. Refer to the fire weather section for more information.

- The Storm Prediction Center has a marginal (level 1 out of 5) risk for severe storms late this afternoon and evening. Hail and damaging winds are the primary risks.

- Northwest flow will result in cooler than normal temperatures Tuesday through Friday with a slight warm-up next weekend.

SHORT TERM /THROUGH TONIGHT/

Issued at 206 AM CDT Mon May 4 2026

Quiet conditions will be seen through sunrise.

By mid to late morning winds will be on the increase across the area with gusts up to 30 mph possible through the afternoon. The strong winds will allow the atmosphere to deeply mix and drop dew points across the area. The combination of winds, low humidity levels and warm temperatures will create a marginal fire risk across the area from late morning through the afternoon in spite of the rapid green up across the area. Refer to the fire weather section for more information.

There were many reports yesterday of blowing dust in central and northern Illinois; generally along/east I-39 and I-55. With wind speeds forecast to be lower than yesterday, areas of blowing dust do not appear likely. Spotty blowing dust from farm fields are possible.

With deep mixing dropping dew points during the day, there are questions regarding convection developing in the afternoon.

All models show the best forcing is along and behind the front suggesting an anafront. However, closer inspection indicates the front is not a true anafront nor is it a katafront. It is a hybrid mix of the two.

The very short term models delay any convective initiation until late afternoon. This trend is reasonable given the marginal low level moisture. If the delay trend continues, then convective initiation looks to occur between 4 and 6 PM and would be isolated due to the limited moisture.

Once convective initiation occurs, the question is how widespread will storms become. Based on the 00z extended run of the HRRR, isolated storms look to be the preferred mode with storms possibly reaching a 25-35% coverage east of the Mississippi during the evening.

During the late evening and overnight hours, an upper level disturbance moves through the area behind the front and the LLJ increases ahead of the front. This disturbance combined with the post-frontal forcing and LLJ impinging upon the southward moving cold front may be enough to generate isolated to scattered (10-35%) coverage of showers or areas of light rain behind the front.

LONG TERM /TUESDAY THROUGH SUNDAY/

Issued at 206 AM CDT Mon May 4 2026

Tuesday through Wednesday Assessment...a certainty (>97%) of cooler than normal temperatures. Low (<20%) confidence on rain.

Northwest flow will result in cooler than normal temperatures across the area. A surface low that is forecast to move along the cold front is now taking a further south track. As a result, the model consensus is keeping areas north of I-80 dry Tuesday through Wednesday with a 20-60% chance of rain south of I-80. Given the anomalously low H5 heights over the Great Lakes, a further southward trend in the rain has a high probability of occurring. I expect the model consensus to continue lowering rain chances south of I-80 over the next several model cycles. The ECMWF-AIFS supports this line of thinking with it indicating Tuesday through Wednesday having a high probability of being dry.

Thursday through Friday Assessment...low to medium (20-50%) confidence on daily diurnal showers

The model consensus continues to have two respectable upper level disturbances moving through in the flow aloft Thursday and Friday. However, the model consensus has trended down on the rain chances; keeping Thursday dry with only 20% chances Thursday night through Friday evening. Given the limited moisture associated with each disturbance, the downward trend is reasonable. I still expect some isolated diurnal showers each day but areal coverage will likely be 10-20 percent at best.

Saturday through Sunday Assessment...high (>80%) confidence on a slight warm-up

The model consensus agrees that there will be a slight warm-up over the weekend that will push high temperatures into the lower 70s.

Rain chances are more questionable.

The model consensus has Saturday dry with a system arriving Saturday night into Sunday. Given differences in track and timing between the models, rain chances are only at 30 percent.

The overall flow pattern across the CONUS has a ridge along/west of the west coast with a fairly deep trof along the east coast. All models show some de-amplification of the pattern occurring by next weekend. The rain chances boil down the the track of the weekend system. Based on the flow pattern and the ECMWF-AIFS/AIGFS, the better rain chances are definitely south of the IA/MO border.

AVIATION /12Z TAFS THROUGH 12Z TUESDAY/

Issued at 621 AM CDT Mon May 4 2026

Trends in the HRRR model since the 06z/04 TAF issuance show dew points dropping indicative of deep mixing. Considerable low level mechanical turbulence will be seen as winds gust up to 30 knots with slightly lower gusts once the cold front moves through. The deep mixing raises questions about diurnal convection developing. HRRR has delayed convection until 22z/04 and is now down to very isolated coverage through 03z/05. A secondary surge of moisture aloft may initiate isolated to scattered SHRA after 06z/05.

FIRE WEATHER

Issued at 206 AM CDT Mon May 4 2026

Strong daytime heating will result in deep mixing of the atmosphere late this morning and afternoon. Winds gusting up to 30 mph combined with warm temperatures will drop afternoon humidity levels into the 25 to 35 percent range. The rapid green up from the heavier than normal April rainfall will partially mitigate the fire risk. However, if the deep mixing causes humidity levels to drop lower than forecast, then the fire risk would be higher.

Based on the available data, the fire risk from late this morning through the afternoon is elevated but at the low end of elevated. Any outdoor burning should still be postponed.

DVN WATCHES/WARNINGS/ADVISORIES

IA...None. IL...None. MO...None.